ABSTRACT
Information retrieval 1 (IR) is a rich field with a long history dating back to the 1940s. These decades of research have produced some extremely powerful techniques that have revolutionized, among other things, bibliographic research. However, despite the progress, many — perhaps most — IR systems are far less powerful than we would wish. There are serious problems limiting IR system effectiveness, and competing suggestions about how to overcome them. In this chapter I follow a particular landscape of IR research, highlighting certain problems with traditional IR methods and describing various methods used to alleviate them. Before proceeding, though, it is worth being clear on exactly what an IR system is supposed to do.
